Novel iron-based polynuclear metal complexes [Feᴵᴵ(L)(CN)₄]₂–[Feᴵᴵᴵ(H₂O)₃Cl]₂: Synthesis and study of photovoltaic properties for dye-sensitized solar cell

A series of novel polynuclear iron-based photosensitizers (1–3) with cyano-bridged to form a molecular square were synthesized and their optical, electrochemical, and photovoltaic properties were investigated. The modification of anchoring groups with 4,4'-dicarboxy-2,2'-bipyridine, 2,2'-bipyridine, and 4,4'-dimethoxy-2,2'-bipyridine does not show significant changes on the both absorption and electrochemical properties of these iron-based dyes. This indicates that the polynuclear iron-based photosensitizers have better flexibility to regulate their physical properties of solubility, surface absorption, and thin-film formation for device preparation. The polynuclear new dyes show power conversion efficiencies ranged from 0.43 to 0.48% that is almost the best system among the published iron-based photosensitizers. These iron-based dyes were able to chemisorb on TiO₂ surface efficiently and then promoting electron injection and photocurrent generation in a dye-sensitized solar cell with solar irradiation. Copyright © 2018 Pleiades Publishing, Ltd.